I find these individual blogs more valuable than a company blog.
I want to hear the success story from the designers perspective, another from the technical lead, and another from an engineering point-of-view and so on.
I think that kind of blog is very different. The general purpose blog is for customers (or potential customers). The Tech/Eng/BD blogs are great for startup enthusiasts, but aren't going to be very efficent channels to get customers to sign up. Unless the potential customer fits one of those groups and is interested on a couple levels. I agree with you though, I find the behind the curtain stuff fascinating.
I want to hear the success story from the designers perspective, another from the technical lead, and another from an engineering point-of-view and so on.